Evaporation is a vacuum coating technology of physical vapor deposition, in which evaporation material is placed in a crucible, and through heating the crucible, the material is converted from solid to gas atoms, atom groups or molecules, and then accumulated on the surface of a substrate to be coated to form a film.
In evaporation process for manufacturing an OLED (Organic Light-Emitting Diode) display device, a linear evaporation source is adopted, with a crucible as the key component thereof. The existing crucible adopted in the evaporation process for manufacturing an OLED display device is designed to be an integrally cast crucible with a transverse span of, for example, about 0.8 m. As shown in FIG. 1, the existing integrally cast crucible includes a main cavity 10 for containing evaporation material, and a cover plate 20 covering the main cavity 10. Gas outlets 21 are provided on the cover plate 20, and generally, nozzles 22 are also provided correspondingly above the gas outlets 21, as passages for ejection of gas converted from solid evaporation material when the main cavity 10 is heated. However the inventor finds that as the transverse span (the span in the left-right direction shown in FIG. 1) is relatively long, there are at least the following problems: 1. as filling of the evaporation material, in order to uniformly add the material in the main cavity 10, an operator needs to fill the evaporation material while moving, which is very likely to cause leakage, drift and loss of the material, and as the OLED evaporation material is very expensive, the cost is increased due to the leakage, drift and loss; 2. the existing OLED evaporation material is powdered, and cannot be controlled to be uniformly distributed in the main cavity 10 during filling, which is likely to result in a thickness difference of the film formed by evaporation; 3. existing weighting scales cannot accurately measure the weight of such a large crucible and a total amount of the added material; and 4. after completion of evaporation, the material adhered in the main cavity 10 is difficult to clean.